Device for mounting flexible printing plates



United States Patent [72] Inventor Josef Boehm Waldbuttelbrunn, Germany [21 Appl. No. 794,306

[22] Filed Jan. 27, 1969 [45] Patented Oct. 27, 1970 [73] Assignee Schnellpressenfabrik Koenig & Bauer Aktiengesellschafl, Wurzburg, Germany Primary Examiner-Robert E. Pulfrey Assistant Examiner-J. Reed Fisher Attorney-Jones & Lockwood ABSTRACT: A lockup for a plate on a plate cylinder is provided. There are in the illustration, two slots in the plate cylinder one for each end of an arcuate plate being mounted. A first clamping jaw extends in one of the slots and is mounted for pivotal movement about a shaft within the plate cylinder, This jaw has an integral lever arm with an adjusting screw threadedly received in the plate cylinder whereby turning the screw will pivot the clamping jaw. Cooperating with this first clamping jaw is a radially extending bar in the slot and a clamping element in the form of an elongated elastic cord. One radially inwardly bent end of the arcuate plate is received between the first clamping jaw and the elastic cord. The adjusting screw rotates the clamp to press the plate end against the elastic cord or release it from pressing against the elastic cord. There is another pivotally mounted clamping jaw in the other slot in the plate cylinder and it clamps the other radial inwardly bent end of the arcuate plate against another elastic cord that abuts another radially extending bar in this other slot. There is a like integral lever arm on the second pivoted clamping jaw. This other lever arm has a compression spring mounted in the plate cylinder that presses continually against the lever arm of the second clamping jaw when an arcuate plate is locked up. By rotating the adjusting screw for the first clamping jaw in the proper direction the arcuate plate is adustably positioned along the arcuate surface of the plate cylinder. The compression spring in the system applies a bias force on the adjacent arcuate plate end, Other pairs of such clamping jaws may be positioned about the plate cylinder. In the disclosure there are two diametrically positioned slots and two pairs of clamping jaws for two arcuate plates.

DEVICE FOR MOUNTING FLEXIBLE PRINTING PLATES BACKGROUND OF THE INVENTION The invention relates to a device for mounting flexible printing plates onto plate cylinders of rotary printing presses by means of two clamping jaws arranged in a groove of the plate cylinder and counteracting parallel to the central shaft of the cylinder to the opposing clamping surfaces. These form a narrow gap between the leading and the rear edge of the printing plate which are crimped at the edges of the clamping jaws positioned close to the cylinder jacket so they can be pressed by means of a clamping element arranged between the clamping surfaces and extending along the clamping jaws, whereby each clamping jaw is arranged at one end of a two-arm lever and a spring-loaded bolt is engaged at the other end of the lever carrying the one clamping jaw and at the other end of the lever carrying the other clamping jaw for moving the two clamping jaws to each other,

A device of this kind has become known by the German Pat. No. 1,265,164. It is suitable for clamping a flexible printing plate onto the plate cylinder the length of which corresponds approximately to the circumference of the plate cylinder.

This patent does not make any reference to what process has to be taken in order to mount two or three wrap-around plates in circumferential direction of the plate cylinder, incorporating the advantages of the circumferential register adjustment and a narrow nonprinting gap.

SUMMARY OF THE lNVENTlON This, however, is the object of the invention. The problem is solved by providing each clamping jaw to be pressed against the clamping element extending along the clamping jaws which itself is resting against a bar extending over the entire plate width and being narrow in the circumferential direction of the printing plate and firmly connected to the plate cylinder.

Owing to this solution the nonprinting area is increased by the width of the bar and of the additional clamping element. This increase in width is, however, relatively small and insignificant in comparison to the advantages of the possible shifting the plate and the simpler design than the known plate lockups.

BRIEF DESCRIPTION OF THE DRAWING An embodiment of the invention is hereinafter described by way of example with reference to the accompanying drawing, but it is clearly to be understood that the invention is by no means restricted to the details of the embodiment.

The drawing shows a cross section through a plate cylinder on which two printing plates are mounted.

DESCRIPTION OF THE PREFERRED EMBODIMENT Two printing plates 2 and 4 are mounted on the plate cylinder 1. They are tightened by the clamping jaws 21, 22 and 41, 42. Between the clamping jaws 21 and 42 there are two clamping elements 23 and 44 elastic cord like shaped which are pressed onto the bar 45 by the action of the clamping jaws. The bar 45 is mounted on plate cylinder 1.

As shown in the basic Pat. No. 1,265,164, the clampingjaws 22 are rocked about the shaft 26 by means of the adjusting screw 27 mounted at the lever 28. The clamping jaw 21 operated by spring 29 which rocks it about shaft 31 by means of its lever arm 30. When operating adjusting screw 27 the elastic cord 24 is compressed and plate 2 is clamped. Owing to this, spring 29 is deformed. When tightening further the adjusting screw 27, plate 2 can be shifted in circumferential direction to the plate cylinder in and against the direction of action of the spring 29.

The parts of the lockup devices for plate 4 are designated with the numbers 41 to 51 according to the parts 21 to 31 for the lockup device for plate 2.

I claim:

1. Apparatus for mounting a flexible arcuate plate having generally radial inwardly bent ends on a plate cylinder of a rotary printing press having at least a pair of slots therein for receiving said ends of the plate and extending parallel to the central shaft of the cylinder, a generally radially extending bar in each slot on the cylinder, a first clamping jaw pivotally mounted in the cylinder and extending in said slot, an attached lever arm on said first clamping jaw, a spring means mounted in the plate cylinder and urging said first clamping jaw towards the adjacent in bent end of said arcuate plate and against an elongated clamping element abutting said bar in said slot, a second clamping jaw extending in said second slot and pivotally mounted in said cylinder, a clamping element abutting the bar extending in said second slot, said second clamping jaw having an attached lever arm and an adjusting screw member threadedly received in the cylinder for rotating said second clamping jaw against the other inbent end of the arcuate plate that presses against said clamping element extending in said second slot, said adjusting screw when rotated in one direction urging said arcuate plate in one circumferential direction against the bias force of said spring means acting on the first clamping jaw and on rotation in the other direction permitting the bias force of said spring means to rotate the first clamping jaw to move the arcuate plate in the reverse direction on the surface of said plate cylinder.

2. Apparatus according to claim I wherein the clamping elements in said slots abutting said generally radially extending bars are elongated elastic cords.

3. Apparatus according to claim 1 wherein the clamping jaws are pivotally mounted on shafts and wherein their respective attached lever arms are mounted on said shafts and keyed to the clamping jaws.

4. Apparatus according to claim 1 wherein said printing cylinder has arcuate surfaces in pockets adjacent said slots for receiving said clamping jaws, said jaws having arcuate surfaces received adjacent said arcuate surfaces in said pockets.

5. Apparatus according to claim 2 wherein the clamping jaws are pivotally mounted on shafts and wherein their respective attached lever arms are mounted on said shafts and keyed to the clamping jaws.

6. Apparatus according to claim 2 wherein said printing cylinder has arcuate surfaces in pockets adjacent said slots for receiving said clamping jaws, said jaws having arcuate surfaces received adjacent said arcuate surfaces in said pockets.

7. Apparatus according to claim 3 wherein said printing cylinder has arcuate surfaces in pockets adjacent said slots for receiving said clamping jaws, said jaws having arcuate surfaces received adjacent said arcuate surfaces in said pockets. 

